The present invention is a continuation-in-part of U.S. patent application Ser. No. 07/410,757 filed Sep. 22, 1989 which has now been allowed for issuance as a patent, and is incorporated hereby by reference. In the disclosure of the aforesaid patent application, there is provided a vehicular internal fan ventilator using a packing rubber for sealing the gap between window glass and door frame upper trim of a vehicle. The packing rubber comprises a retainer rib at the top and a window glass channel at the bottom. It is cut into proper size according to the window glass channel of a vehicle to be sealed, and the retainer rib is inserted into the window glass channel of a vehicle to let window glass be lifted to insert into the window glass channel so that the packing rubber becomes firmly retained between window glass and door frame of a vehicle. This structure of packing rubber is still not very satisfactory in use. Because the curvature of the top edge of the window glass of the car doors of a vehicle may vary with one another, gap may be not completely sealed between a window glass and the packing rubber when a window glass is lifted to insert into the window glass channel of the packing rubber. Further, after a window glass is moved down, supporting force to the packing rubber is released and the packing rubber may drop easily due to shaking of a vehicle.